As researchers work to improve the accuracy of flu forecasts, local health officials say this winter’s flu season has already begun.
Juan Rodriguez, chief epidemiologist with the Denton County Health Department, has counted about 30 cases of influenza in Denton County this week, compared to only two cases at this time last year. Because outbreaks often follow a similar curve each year, Rodriguez expects 40 more cases this week.
New strains have emerged this year, and that may help explain the flu’s early debut, he said. People don’t have the protection afforded from the shots administered in the past few years. Vaccines being administered this season anticipated two of the new strains, Rodriguez said.
“The new vaccine is matching pretty well, so it should give good protection,” Rodriguez said.
Some doctors, nurses and hospitals report their flu cases, but they are not required to. That makes surveillance data less robust than it is for other diseases that must be reported, such as West Nile virus, Rodriguez said.
To test the ability to make flu forecasts, researchers at Columbia University in New York and the National Center for Atmospheric Research in Boulder, Colo., worked together on the same kind of statistical model that meteorologists use.
A flu season can vary from year to year, and from region to region. This year, Texas health officials have said influenza has emerged the earliest they’ve seen in about a decade.
The lead researcher, Jeffrey Shaman, of Columbia’s Mailman School of Public Health, said that such “skillful forecasts” — the ability to predict something with some percentage of certainty — requires three pieces of information: a mathematical model, real-time observations and a way to bring the data into the model.
Shaman and Alicia Karspeck, at the National Center for Atmospheric Research, ran both the model and actual flu data from New York City from the winters of 2003-04 to 2008-09 to see whether the model could predict the timing and severity of the flu season those years.
The results of the pilot study showed that the model could predict the peak of the flu season about seven weeks in advance.
Shaman has also researched whether flu’s transmission is affected by humidity. Some data has shown that the virus can be more readily transmitted in drier air, he said.
Currently, Shaman and Karspeck are checking this season’s outbreak against real-time data in New York City. But it will take some time before they can check the ability of the model to predict flu peaks in other regions.
Some of that real-time data came from Google Flu Trends, Karspeck said. Several years ago, the company’s programmers found a strong correlation between certain searches and flu’s emergence. The Centers for Disease Control and Prevention have worked with Google on their own estimates of outbreaks.
Along with what is known about flu outbreaks and about the number of people infected on a daily basis, “essentially what is new and interesting about the study is this rich source of [Google] data,” Karspeck said.
Irene Eckstrand of the National Institute of General Medical Sciences at the National Institutes of Health, which helped pay for the study, said she had been skeptical of the possibility of predicting infectious diseases.
“I’m encouraged that we may be able to anticipate how illnesses emerge — this is a useful thing,” Eckstrand said.
Statistical models could be another tool for public health officials as they plan their response to outbreaks, she said. It could also help individuals.
Not only could people exercise more care — washing hands, getting a vaccine — at the beginning of an outbreak, but could also better monitor how they feel.
Dr. Rouhy Prueitt, urgent care director for Denton Regional Medical Center, said that if people come in within the first 48 hours of flu symptoms, treatment can help make symptoms less severe.
Doctors encourage patients to come in when they have a fever, cough and sore throat. They can swab to test for the virus and prescribe medication that “really takes the edge off,” Prueitt said.
That relief is particularly important for people with other health problems, such as asthma or diabetes.
Although the hospital is seeing flu cases earlier this year, they haven’t been more severe than years past, Prueitt said.
Similarly, the Texas Health Presbyterian Hospital Denton staff has not seen anything unusual in this year’s outbreak.
“Most all of the cases have not been serious,” hospital spokeswoman Elizabeth Long said in an e-mail. “We’d like to remind folks that it is not too late to get the flu vaccine.”
To help stop the spread of the virus, Stephanie Sandmann, a registered nurse in the hospital’s emergency department, reminds people to wash hands, cough and sneeze into their sleeve, and stay home whenever you have fever, cough, sore throat, body aches, chills and fatigue.
PEGGY HEINKEL-WOLFE can be reached at 940-566-6881. Her e-mail address is firstname.lastname@example.org.